Monster Manic Halloween: With two dance floors, some of the city’s hottest DJs and a $1,000 costume contest. (Adults only; 21 and over with costume.) Tickets: $35-$70. 9 p.m.-2 a.m. Saturday at Parc 55 Hotel, S.F. More information at monstermanic.eventbrite.com. less

Monster Manic Halloween: With two dance floors, some of the city’s hottest DJs and a $1,000 costume contest. (Adults only; 21 and over with costume.) Tickets: $35-$70. 9 p.m.-2 a.m. Saturday at Parc 55 ... more

Photo: Http://www.monstermanic.com/

Monster Manic Halloween: With two dance floors, some of the... Photo-5362368.72655 - SFGate

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Monster’s Ball 2013: The USS Hornet and 107.7 The Bone present Monster’s Ball, on Saturday at the USS Hornet Aircraft Carrier. Join the gang and the top DJs from The Bone and party the night away. Live performances by ZEBOP!, the Cocktail Monkeys and silk acrobat Ariel Performer. Enter the costume contest and the winner will receive a $500 cash prize, other prizes to will be awarded to runners up. (Please note this is an adult event.) Tickets $30-$35. More information at www.hornetevents.com . less

Monster’s Ball 2013: The USS Hornet and 107.7 The Bone present Monster’s Ball, on Saturday at the USS Hornet Aircraft Carrier. Join the gang and the top DJs from The Bone and party the night away. Live ... more

Thrill the World Bay Area: Annual flash mob is a celebration of dance and community inspired by Michael Jackson’s hit song. The group performance is at 2 p.m.; registration is required if you want to dance. (Crash course workshop at 11 a.m.) Free; $5 donation requested. Registration begins at 10:30 a.m. Saturday at Studio One Art Center, Oakland. More information at www.thrilltheworldbayarea.com. less

Thrill the World Bay Area: Annual flash mob is a celebration of dance and community inspired by Michael Jackson’s hit song. The group performance is at 2 p.m.; registration is required if you want to dance. ... more

Halloween Massive: “Beyond the Grave”: This ever-popular party (it has sold out 10 years in a row) features a costume contest and top 40, house, hip-hop and club hits. (Adults only; 21 and over with costume.) Tickets: $39-$109. 9 p.m.-2 a.m. Saturday at the Westin San Francisco Hotel. More information at www.halloweenmassive.com . less

Halloween Massive: “Beyond the Grave”: This ever-popular party (it has sold out 10 years in a row) features a costume contest and top 40, house, hip-hop and club hits. (Adults only; 21 and over with ... more

Halloween Brew Crawl: Downtown Pleasanton merchants and local breweries will come together for a night of trick-or-treating for adults. Patrons can shop along Main Street while sampling a variety of beer and tasty bites at 25 locations. Costumes encouraged. Tickets $30-$35; includes beer tastings at 25 downtown locations, a commemorative beer glass and tasting map. 5-8 p.m. Saturday. More information at instagift.com/pda. less

Halloween Brew Crawl: Downtown Pleasanton merchants and local breweries will come together for a night of trick-or-treating for adults. Patrons can shop along Main Street while sampling a variety of beer and ... more

Family Halloween Day: The Randall Museum will be transformed into a Halloween haunt with a gamut of ghoulish games, creepy crafts, tricks and treats and more. Costumed revelers can explore the Twilight Forest, take a stab at pumpkin carving, and enjoy live entertainment. Free admission. 10 a.m.-2 p.m. Saturday at the Randall Museum, S.F. More information at www.randallmuseum.org. less

Family Halloween Day: The Randall Museum will be transformed into a Halloween haunt with a gamut of ghoulish games, creepy crafts, tricks and treats and more. Costumed revelers can explore the Twilight Forest, ... more

Photo: Jennifer Zee

Family Halloween Day: The Randall Museum will be transformed... Photo-5362373.72655 - SFGate

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Treasure Island Flea: Shop 300 curated indie, craft and antique vendors and enjoy the Halloween festivities for all ages. The market will feature a pumpkin patch with over a hundred locally grown pumpkins. Tickets: $3; under 12 free. 10 a.m.-4 p.m. Saturday-Sunday on Treasure Island. More information at www.treasureislandflea.com . less

Treasure Island Flea: Shop 300 curated indie, craft and antique vendors and enjoy the Halloween festivities for all ages. The market will feature a pumpkin patch with over a hundred locally grown pumpkins. ... more

Baby Loves Disco: Kids and parents are invited to come in costume for prizes, contests, tricks and lots of treats at this family dance party. Tickets: $15-$55. Noon-2:30 p.m. Sunday at Temple SF. More information at www. babylovesdisco.com. less

Baby Loves Disco: Kids and parents are invited to come in costume for prizes, contests, tricks and lots of treats at this family dance party. Tickets: $15-$55. Noon-2:30 p.m. Sunday at Temple SF. More ... more